Solvation of anions in acetonitrile solutions: FTIR and quantum chemical study for Br-, ClO4-, AsF6-, and CF3SO3

Alexander M Erkabaev; Tatyana V Yaroslavtseva; Olga G Reznitskikh; Olga V Bushkova

doi:10.1016/j.saa.2019.117873

Solvation of anions in acetonitrile solutions: FTIR and quantum chemical study for Br^-, ClO₄^-, AsF₆^-, and CF₃SO₃

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 15:229:117873. doi: 10.1016/j.saa.2019.117873. Epub 2019 Nov 29.

Authors

Alexander M Erkabaev¹, Tatyana V Yaroslavtseva¹, Olga G Reznitskikh¹, Olga V Bushkova²

Affiliations

¹ Institute of Solid State Chemistry UB RAS, Pervomaiskaya st., 91, Ekaterinburg 620990, Russia.
² Institute of Solid State Chemistry UB RAS, Pervomaiskaya st., 91, Ekaterinburg 620990, Russia; NTI Competence Center for New and Mobile Power Sources Technologies of the Institute of Problems of Chemical Physics RAS, Academician Semenov av. 1, Chernogolovka, Moscow region 142432, Russia. Electronic address: bushkova@ihim.uran.ru.

PMID: 31813727
DOI: 10.1016/j.saa.2019.117873

Abstract

Anion solvation in acetonitrile solutions was comparatively studied using FTIR spectroscopy and quantum chemical calculations at the RTF + MP2/6-311G** level of theory with solvation model density (SMD) corrections. Infrared spectra for all stable anionic complexes X^-(CH₃CN)_n (where X^- = Br^- (monatomic halide), ClO₄^- (polyatomic tetrahedral), AsF₆^- (polyatomic octahedral), CF₃SO₃^- (polyatomic ethane-like) and n = 1-8) were calculated and subsequently used in the analysis of the FTIR spectra of (Bu₄N)X and LiX acetonitrile solutions across a wide range of concentrations. Spectroscopic manifestations of solvation were established for all X^- examined. The results for all four anions under investigation were generalized to reveal the regularities of anion solvation by acetonitrile.

Keywords: Acetonitrile solutions; Anionic solvates; Infrared; Quantum chemical calculations; Spectroscopy.